Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, Zhejiang Sci-Tech University, Hangzhou, 310018, Zhejiang, China.
Analyst. 2022 May 3;147(9):1915-1922. doi: 10.1039/d1an02088a.
Determining the configuration and conformation of peptides is crucial for interpreting their structure-property relationships. In this work, we present nondestructive terahertz time-domain spectroscopy combined with density functional theory (DFT) and potential energy distribution (PED) analysis to identify the hierarchical structures of oligopeptides. The characteristic THz spectra of silk fibroin oligopeptides have been measured. Supported by DFT and PED analysis, the intrinsic differences among the dipeptides were identified by the collective vibrational modes of "R" groups and terminal groups linked by molecular chains of amido bonds or benzene rings. For tetrapeptides and hexapeptides, a few weak resonances and intensity differences were distinguished by the vibration mode of the molecular collective network formed by the interaction of amide planes and intramolecular hydrogen bond interactions. According to the THz absorption analyses of amide planes and intramolecular interactions within the molecular chains of silk fibroin oligopeptide isomer pairs, the formation and hierarchical structures were successfully interpreted using THz spectroscopy. This investigation develops a better understanding of the peptide formation mechanism, which further provides guidance in interpreting the formation of silk.
确定肽的结构和构象对于解释它们的结构-性能关系至关重要。在这项工作中，我们提出了非破坏性太赫兹时域光谱结合密度泛函理论（DFT）和势能分布（PED）分析，以识别寡肽的层次结构。已经测量了丝素肽寡肽的特征太赫兹光谱。通过 DFT 和 PED 分析的支持，通过酰胺键或苯环连接的分子链上的“R”基团和末端基团的集体振动模式，确定了二肽之间的内在差异。对于四肽和六肽，通过酰胺平面相互作用和分子内氢键相互作用形成的分子集体网络的振动模式，可以区分出一些弱共振和强度差异。根据丝素肽异构体对酰胺平面和分子内相互作用的太赫兹吸收分析，成功地使用太赫兹光谱解释了形成和层次结构。这项研究加深了对肽形成机制的理解，进一步为解释丝的形成提供了指导。
